Pen



FIG. 1 is a front elevational view of a pen showing my new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof;

FIG. 7 is a perspective view thereof; and,

FIG. 8 is a perspective view of the pen with its cap detached.

The broken lines are for illustrating portions of the pen that form no part of the claimed design. 

CLAIM The ornamental design for a pen, as shown and described. 